Extraction of polyphenols from hybrid Eucalyptus leaves using ultrasound: Parametric and antioxidant studies

In the present study, a medicinal tree named hybrid Eucalyptus was chosen for the extraction of polyphenols from its leaves. Ultrasound has been used for extraction studies, whereas other conventional extraction methods were studied to validate the applied ultrasound assisted extraction method. Various experimental parameters like material to solvent ratio, solvents, and ultrasound irradiation time were employed to obtain the required condition for effective polyphenols extraction. The maximum total polyphenols achieved was 62.24 mg Gallic acid equivalent (GAE)/g of powdered leaves sample with material to solvent ratio of 1:30 and 50% ethanol as solvent with an ultrasonic bath whereas the maximum total flavonoid of 14.20 mg Quercetin equivalent (QE)/g of powdered leaves sample was obtained under the same experimental conditions. The gas chromatography mass spectroscopy (GC-MS) study of the eucalyptus leaves extract had proved that it contains the required polyphenols of high medicinal value. Also, studies were performed to check 2,2-diphenylpicrylhydrazyl (DPPH), ferric reducing anti-oxidant power (FRAP) and 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging potential of the leaves extract.